Surface shown in Eevee but not in Cycles
Thanks Nathan, your comment gave me the courage to dig deeper. Eventually, I found 2 issues.

Because the wood surface was actually generated as the ground when I used 'Setup Tracking Scene', it was set as 'Shadow catcher' in the Visibility section of the object properties.
When I added the cylinder, I added it to the 'background' collection, which was marked as 'holdout' in the same section.

Again, thanks Nathan for your tip, I added a cube above the surface, made it glossy and it rendered fine, which led me to that extra investigation.